---
title: "What's new in Vert.x 4"
category: releases
authors:
  - name: Julien Viet
    github_id: vietj
  - name: Francesco Guardiani
    github_id: slinkydeveloper
  - name: Paulo Lopes
    github_id: pmlopes
summary: >-
  See an overview of all new and exciting features in Vert.x 4, including futures,
  distributed tracing, reactive database clients, SQL templating, and more.
---

Vert.x 4 comes with plenty of new exciting features, some of them have been developed in Vert.x 3 and made available
as tech previews.

Here is an overview of the most important features supported in Vert.x 4.

## User experience

Vert.x 4 has been designed to improve user experience and API's usability while keeping it
fast, un-opinionated, and most importantly fun!

## Callback to the Future

Get away from callback hell and use the power of Vert.x 4 futures.

## Microservices monitoring

Vert.x Tracing supports both [Opentracing](https://opentracing.io/) and [Zipkin](https://zipkin.io/). It also
complements Vert.x Metrics.

## Reactive SQL clients

High-performance reactive SQL clients, fully integrated with Vert.x Metrics and Vert.x Tracing.

## Reactive Redis client

The revamped client API now supports all Redis connection modes, _single_, _sentinel_ and _cluster_, with full
and extensible support for Redis commands.

## SQL templating

SQL Client Templates is a library designed to facilitate building SQL queries.

## Web

Web sessions can now be stored on a external backend such as Redis.

Web routing experience has been improved.

Web validation has never been so easy using the latest Json Schema standards thanks to Vert.x Web validation.

## OpenAPI

The revamped OpenAPI implementation uses Web validation to enforce Contract Driven Development.

## Authentication and Authorization

A set of new modules are available

- `vertx-auth-properties` and `vertx-auth-ldap` to replace the deprecated `shiro` auth.
- `vertx-auth-sql` to work with reactive sql clients instead of blocking jdbc clients.
- `vertx-auth-webauth` as a FIDO2 verified implementation of FIDO2/Webauthn Relay Party.

The `vertx-auth-oauth2` module now supports [PKCE](https://tools.ietf.org/html/rfc7636) as an extra layer of
security to your application.

JSON Web Tokens (JWT) and JSON Web Keys (JWK) have been enhanced to support more algorithms, `EC`, `RS` and `PS`
as well as now fully support certificate chain validations, enabling better verifications.
